speedometer calibration on R bike

[petez]

Is it possible to calibrate the speedometer on an oilhead R bike? I have seen many methods for doing this on K bikes.

[jdiaz]

I used to just multiply all my speedo readings by 0.9......actually, with my LT, I still have to. :clap

[MrFrank]

Originally posted by jdiaz
I used to just multiply all my speedo readings by 0.9......actually, with my LT, I still have to. :clap

Jon,
Wouldn't that be an 11% error? That's a tad high isn't it?

[jdiaz]

Originally posted by Mr. Frank
Wouldn't that be an 11% error? That's a tad high isn't it?
It depends. In the engineering world, we call that "tolerance," not error. Kinda like those exit polls that have a range of confidence. :)

[MrFrank]

Originally posted by jdiaz
It depends. In the engineering world, we call that "tolerance," not error. Kinda like those exit polls that have a range of confidence. :)

Tolerance is in both directions. BMW speedos are always off in the same direction by about the same percentage. That's German engineering. <G>

[Paper]

I tossed my GPS in my tankbag to do a speedo test on my R1100R and was amazed with how accurate it was.
It was never off more than 2 mph at speeds between 20-100 mph..
It was worst at 30 where my speedo showed 30 and the GPS was at 28. At 100 it was only 1.3 mph off..
This was with my Magellan SportTrak Pro with WAAS...

[cat0020]

From my experience, GPS unit can vary on their accuracy.
depending on the refresh rate of the GPS signals, it may take up to 3 seconds before the GPS calculates your speed, so the speed that's displaying on your GPS unit could very well be your speed 3 seconds ago, rather than instant speed.

My R1150RS' speedometer is usually 5-7 mph faster than my Garmin Streetpilot displays on the screen. as the speed gets up to the triple digit, the difference between the two becomes smaller.




Originally posted by Paper
I tossed my GPS in my tankbag to do a speedo test on my R1100R and was amazed with how accurate it was.
It was never off more than 2 mph at speeds between 20-100 mph..
It was worst at 30 where my speedo showed 30 and the GPS was at 28. At 100 it was only 1.3 mph off..
This was with my Magellan SportTrak Pro with WAAS...

[Paper]

You could be very right about the refresh rate, but this was done on a straight, flat road with my ThrottleMeister and looking back and forth between the speedo and the GPS.

All speeds were actually held for about 15 seconds as I glanced back and forth between the two to make sure what I was seeing would be correct.. OK... At 100 I might have been in a little more of a hurry than 15 seconds..

I didn't do this to post it here for your reading or questioning. I did it 2 months ago to find out where my speedo stood in the real world of speed... Or even more so, in the real world of tickets.. Also, I was getting 8 to 10 satellite's information during the entire test.

I did the exact same thing with my Toyota T100 and my VW GTI..
The most amazing part of this was that my BMW has the most accurate speedo.. OK.. Both the car and truck aren't running stock tire sizes, so I'm sure that is a huge factor on them... :cool:

[cat0020]

Originally posted by Paper
All speeds were actually held for about 15 seconds as I glanced back and forth between the two to make sure what I was seeing would be correct.. OK... At 100 I might have been in a little more of a hurry than 15 seconds..


At 100 mph, traveling for 12 seconds.. that's close to 1/3 mile.
I know there isn't much straight and flat roads near my area to safely do that kind of speed and see what's ahead.

:brow

[Paper]

Cat0020,
Ever been to IL?? Rural IL??
Nothing but one mile squares.. Flat one mile squares. At that time the fields were only tilled with nothing even planted yet..

I appreciate your concern for my safety and your questioning of my experiment, but unless you were there, I don't understand why you don't believe me.. I have absolutely no reason to lie. I only told you my findings between my GPS and my speedometer.

Send my your Garmin and I'll do it again, or even better come on over to IL and ride next to me..:dunno

[cat0020]

No offense Paperman, I'm just jealous not have the luxury of nice, flat, straight roads that allow me to open throttle and be safe or keep my license. Good for you.

[Paper]

Testing the speedo is the ONLY thing that flat straight roads are good for.. They suck for everything else.. BAD!!! Unless you like flat spots across your rear tire.:banghead

Lucky for me, Southwestern Wisconsin is a fantastic area of curvy, hilly roads with little traffic. And it's only 1 hour away from the good stuff. I go over there just to put wear on the sides of my tires.:lol

[32232]

A friend who is a local police officer verified my speedo error using radar. Results for a 2001 R1150r were as follows: 80km/h indicated was actually 76km/h, 100km/h was 93km/h, and 120km/h was 111km/h. To convert to mph multilpy by .62.

[awchesley]

My '95 R11GSA was 5 mph fast according to police radar and Garmin III GPS.
My '97 R11RA was 5 mph fast according to same.
My '02 R1150GSA was 7 mph fast according to Garmin III and Garmin 176 and radar readings. On the '02 GS I put a speedo hub with the 3.0 gear ratio on the front from an R11RA and it brought the reading to only 2 mph fast.

Andy
Jennings, La.

[petez]

Judging by the responses, no one knows whether it is possible to adjust the speedo on an R bike. A friend has one, so I will take it apart and see whether it is similar to the K-bike's instrument.

I was able to adjust my K1100 to be absolutely correct at 60 MPH by tweaking an internal potentiometer.

[awchesley]

The only way you can adjust the R models speedo is send it to a reconized speedo shop. They are mechanical speedos.
K models have electric speedo totally different worlds.

[Paper]

It will also depend on what model R bike.. Some have mechanical speedos (R1150R) and others have electronic..

Good luck and let us know how it turns out....

[MrFrank]

I have always heard that the R bike speedos were mechanical as compared to the electronic K speedos.

[KBasa]

My S bike is electronic, but the Tina's R1150R and R11RS are mechanical.

[petez]

I can check easily enough. If there is an electrical speedo sender mounted on the top of the final drive, then the speedo is electric, and presumably can be adjusted the same way the K bikes can.

[KBasa]

Which Rbike are you looking at, Pete? I read a note on the Beeg the other day from Steve Anderson. He has switched the speedo drive unit for a 2.9 unit and his speedo now reads exactly right. He's got a GS.

He's at Morton BMW.

I have no affiliation with Morton's, yadda yadda.

[petez]

The bike in question is an R1100GS, 1999. I asked the owner to check the front wheel hub, and there is definitely a mechanical cable exiting it. There is also no speed sensor wire on the rear hub, as there is on my K1100.
I guess that answers my question - it has a mechanical speedo. I'm surorised that anything that recent still uses a mechanical geartrain.

[Timba]

There's a long thread about it over at advrider.com.

http://www.advrider.com/forums/showthread.php?t=701&page=1&pp=15&highlight=speedometer+bmw


The bottom line seems to be installing speedo hub part number 62 12 2 306 532 which has a 2.875 ratio, compared to the 3.0 ratio stock on the Oilhead GS.

[r1dinman]

I installed that p/n on my '96 GS. The odometer is now accurate acording to the markers on the interstate. I haven't checked the speedometer, as I'd rather live than fiddle with a stopwatch at speed. The revs are now higher in relationship to the speedometer. I think it cut my mileage numbers for the contest by 10%. Buy the way, the optimistic odometer cuts your warranty by 10%. This has been discussed with BMW reps at the rallys. The answer was the usual BS. Anyone who doesn't have a GS should have their parts guy check for a "authority" part number. Cop speedometers are about 2% pesimistic.

Jay

[lorazepam]

My '04 R/RS is within 1mph with the conti tires on it according to my gps. I too found a long straight area of road to check it. I stopped a 90 though.

[MCMXCIVRS]

I've verified my speedo against my GPS as well, and I have found it is dead on accurate. The interesting thing is though, the odometer reads 2% high. It will clock 102 Km for every 100 traveled. I have verified it against both my GPS and several other bikes. I suspect this will also happen if you recalibrated a speedo that was reading low. Just something to think about. One positive note is it gives you an edge in the mileage contest (DOH, now I've blown my secret).

[Colt03]

I have a 2004 GS. Before I replaced the hub with a 2.9 version, my speedometer was 10 % high and my Odometer was 7 % high.

I replaced it with part # 62-12-2-306-532 and the odometer is now accurate to .5 miles per hundred and the speedometer is much closer ie 80 indicated is 78 actual.

HTH

btw this will keep the bike in warranty longer as well. Worth the 45 $.

[Montana]

The R1200C has the sensor on the rear hub, but it is not an electric speedometer. It senses a small wheel that turns inside the hub (mechanical) and picks it up magnetically, turning the impulse into a signal (electric but not 12v) to the speedometer needle.